About 1,500 voters in Swindon have been mistakenly warned that they may not be able to vote in the general election.
In a letter sent by Swindon Borough Council residents were told they would be "removed from the Register of Electors" as they were "not entitled to remain registered" at their property.
Residents were given 14 days to appeal against the move.
The council has since tweeted asking residents to ignore the letter as it was sent "by mistake".
The letter, dated 4 November, said the council was reviewing its "registration entitlement" and it was the authority's "opinion" that the resident was "not entitled to remain registered at this property".
Residents were warned that if they did not appeal against the decision they would be removed from the electoral register.
❗️IMPORTANT NOTICE❗️— Swindon Borough Council (@SwindonCouncil) November 6, 2019
We have been made aware that some of our residents have been sent a letter by mistake in relation to their voter registration.
Anyone who received a letter dated 4 November entitled ‘Notice of review of registration entitlement’ should ignore it.
On Twitter the council later said it had been "made aware that some of our residents have been sent a letter by mistake in relation to their voter registration".
"Anyone who received a letter dated 4 November entitled 'Notice of review of registration entitlement' should ignore it," the council said.
"The error occurred after our printers used an incorrect distribution list. Measures have been put in place to ensure this does not happen again."
The authority said it would be writing to every resident who had received a letter in error to explain what had happened and to apologise.